Illumination



April 25, w H RR N ILLUMINATION Filed March 6,1936 2 Sheets-Sheet 1Fig.1.

l2 l2 /3 5 W \J f /8 Inventor: Ward Harrison H is Attorn qy.

April 25, 1939. w. HARRISON ILLUMINATI ON Filed March 6, 1936 2Sheets-Sheet 2 Inventor: I Ward Harrispn, b fla y His *3 5.19 torne y.

Patented Apr. 25, 1939 UNITED STATES PATENT OFFICE HLUMINATION New YorkApplication March 6, 1936, Serial No. 67,451

1 Claim.

My invention relates to illumination generally and more particularly toa lighting arrangement for the interior of a building.

One of the objects of my invention is to provide a lighting arrangementwhich is substantially free from glare and has a high efficiency.

According to my invention, I provide one or more concave lightconcentrating reflecting surfaces, preferably in the shape of troughs,at the c'eiling of the room. One or more light sources are locatedadjacent the focus of each of said reflecting surfaces or troughs, andreflectors are preferably disposed under each of said light sources todirect the light upward to the adjacent trough from which it isredirected downward into the room. In this way each of the reflectingsurfaces or troughs illuminates substantially only the area directlybelow! it so that the troughs will appear to be very dimly lightedexcept for that portion directly above the observers head which isnormally out of the line of his vision. Since nearly all the light isdirected straight down and very little toward the side walls, theefliciency of illumination is very high. Further features and advantagesof my invention will appear from the following detailed description ofspecies thereof.

In the drawings Fig. l is a plan view, looking upward, of a lightingarrangement comprising my invention; Fig. 2 is a section taken alonglines 2--2 of Fig. 1; Fig. 3 is a section through one trough and itslighting unit on an enlarged scale; and Figs. 4 and 5 are sectionsthrough the troughs and lighting units of modified arrangements of myinvention.

My invention is embodied in illuminators which are preferably built intothe ceiling of a room or office, etc., as shown in Figs. 1, 2 and 3. Inthis instance three substantially parabolic troughs l0 form all but theextreme edges ll of the ceiling and a plurality of lighting units l2 aresuspended at intervals so that each illuminates a portion of a trough.The lighting units, as shown in Fig. 3, each comprise a light source [3which is preferably located at the focus or focal line of the parabola,and a reflector 14 which directs the light upward to the trough. Lips ISon the reflector l4 prevent the light from striking the trough at toosharp an angle so that the light is kept away from the side walls of theroom as much as. possible. The light source l3 may consist of anincandescent lamp which is mounted in a socket l6 which in turn ismounted in an enclosure IT. The lamp bulb may be of clear or frostedglass and the reflector l4 and parabolic trough ID are preferably ofbrushed or oxidized aluminum. A polished trough is not desirable sincesharp lines of light appear on the reflector. A metallic coating sprayedor brushed onto the trough may 5 also be used although the surface mustgive a limited amount of diffusion. White paint would not besatisfactory due to its excellent diffusing properties. The light uniti2 is supported by pipes l8 and IS, the latter of which is fastened tothe ceiling adjacent to the trough. The edges of the parabolic trough l0may extend above or below the. focus but in either case the reflector l4must be formed so that the light strikes only the trough and is notprojected into the room directly.

Obviously in the arrangement just described the trough In illuminatessubstantially only the area directly below it so that the troughs willall appear to be very dimly lighted except for H that portion directlyabove the observers head which is normally out of the line of hisvision. In some instances it may be found desirable to illuminate theside wall in which case the lighting unit l2 can be moved sideward asshown in dotted lines in Fig. 3 so that the light is directed to oneside rather than straight down.

Other types of lighting units such as those shown in Figs. 4 and 5 mayalso be used. In Fig. 4 the lamp I3 is mounted base upward in a socket20 which is supported by a pipe 2| extending downward from the center ofthe trough ID. The reflector M is mounted below the lamp IS on arms 22extending from the socket 29. In Fig. 5 the lighting unit is comprisedof a :33 trough-shaped reflector 23 which is coextensive with the troughl0 and is supported by a pipe 24 which extends downward from the troughIll and supports a plurality of. light sources l3.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

A. room lighting arrangement comprising a concave light concentratingtrough having a reflecting surface and located at the ceiling, aplurality of light sources dispose'd adjacent the focal line of saidtrough, and a reflector disposed under each of said light sources andadapted to direct light upward to said trough from which it isredirected downward each of said reflectors having an upwardly extendinglip on each side thereof in the longitudinal direction of said troughfor confining the light from the light source located therein to adefinite portion of said trough.

WARD HARRISON.

